Tire pressure light: a puncture, or just the cold?

What the warning actually means

The symbol is an exclamation mark inside a cross-section of a tire. It monitors pressure, and a change in temperature alone can trigger it with no puncture at all.

Common causes

• A cold snap. Pressure drops roughly 1 PSI for every 10 °F, about 5 to 6 °C
• A slow leak in one tire
• A puncture
• A faulty sensor, or wheels that have just been changed

What to do now

1. Check the pressure on all four tires, and the spare if you carry one.
2. Use the value on the sticker in the driver's doorjamb.
3. Inflate, then see whether the light goes out after a short drive.
4. If it returns within a few days, you have a leak.

What people often get wrong

That the light means a puncture. A cold snap alone is often enough: pressure drops roughly 1 PSI for every 10 °F the temperature falls.

When the car must go to a workshop

If the pressure falls again shortly after inflating, the tire should be checked for a leak or damage.

Read next

• ABS light on: do the brakes still work?
• Snowflake on the dashboard: an ice warning, not a fault
• Traction control light: flickering, or staying on?
• How to check tire pressure, and how often to do it
• Uneven tire wear: what the pattern says about the car

This page is general information and does not replace a professional assessment. Symbols, codes and behaviour vary between makes. Always check the handbook for your own car.